Two thousand years ago, Native Americans created thousands of mounds and geometrically shaped earthworks across the Eastern Woodlands. Many are larger than Stonehenge; most are aligned to celestial events. Among the most impressive of these earthworks were those created by people of the Adena and Hopewell cultures in south and central Ohio. This book presents one of the most comprehensive and detailed studies of the Ohio earthworks ever written. More than one hundred sites are documented using on-site photographs, maps, and LiDAR imagery. Using these data the author assesses each earthwork relative to its astronomy, geometry, mensuration, and landscape setting. The author then shows how earthworks were integral to Adena-Hopewell religious beliefs and practices. For the Adena-Hopewell, the landscape - to include earth, sky, and water were part of who they were. To move through the landscape was to engage with the sacred. Using new approaches drawn from relational archaeology and state of the art technology, this book examines and explains the deep connection between ancient Native Americans and the land.